Read from source: https://edition.cnn.com/2020/09/28/tech/microsoft-outage/index.html
Microsoft 365 suffers outage across the US
Microsoft attributed the outage to a recent change to the platform initially, but later indicated it was “not observing an increase in successful connections after rolling back a recent change. We’re working to evaluate additional mitigation solutions while we investigate the root cause.”
According to Down Detector, a website that tracks internet outages, users reported issues with logging in, server connection and Outlook.The downtime began around 5 pm ET for Office 365, according to the site, and is heavily affecting users in the California and Washington areas.